CACNA1C and attention deficit-hyperactivity disorder: CACNA1C, encoding the α1 subunit of the L-type voltage-gated calcium channel (LTCC) Cav1.2, is one of the most robust and consistently replicated genetic risk factors for multiple psychiatric disorders including schizophrenia (SCZ), bipolar disorder (BPD), major depressive disorder (MDD), autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) [1, 2].